Absorbent pad

ABSTRACT

D R A W I N G ABSORBENT PAD HAVING A PULP FILER, WADDING ENVELOPE, AND BODY CONTACTING COVER OUTSIDE THE ENVELOPE WHICH IS SHORTER THAN THE PAD IS LONG, THUS TO LEAVE END MARGINS OF THE PAD UNCOVERED. THE APARATUS AND METHOD FOR FABRICATING SUCH A PAD INVOLVES SUPERIMPOSING SEPARATE PULP MATS, ONE OF WHICH IS COMPRESSED BEFORED SUPERIMPOSITION IN ORDER THAT THE COMPRESSED MAT FUNCTIONS AS A FLOW DISTRIBUTION PLY, SUBDIVIDING THE SUPERIMPOSED MATS INTO DISCRETE PAD FILLERS WITH GAPS THEREBETWEEN, ENCASING THE SPACED PAD FILTERS IN A WADDING ENVELOPE WHICH IS CONTINUOUS ACROSS THE GAPS, CROSS SEALING THE ENVELOPE ACROSS THE GAPS TO FORM A CONTINUOUS WADDING ENVELOPE TUBE WITH LINKS INTERCONNECTING THE SPACED FILLER PADS, AND APPLYING THE BODY CONTACTING COVER SHEET THERETO.

C. G. JOA

ABSORBENT PAD May 3o, 1972 4 Sheets-Sheet 1 Filed Aug l5 J 969 INVENTORC027* 6. Jon

@YMALL/wm ATT o 52H EYS C. G. JOA

ABSORBENT PAD May 30, 1972 4 Sheets-Sheet 2 FiLed Aug. l5 .1969

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INVENTO R ATTORNEYS dier 6m .Jon

BY w, W, lmd'cww C. G. JOA

ABSORBENT PAD May 30, 1972 4 Sheets-Sheet 3 Filed Aug. l5. 1969 )NVENTOZ Caer 6. J0@

d ATTO QNEYS May 30, 1972 c. G. JOA 3,666,611

AUSORBENT PAD Filed Aug. 12.1. 19m

4 Sheets-Sheet 4 rm/Emol @der 6. Jon

BY M, #Mm

AT TQRMEYS United States Patent() U.S. Cl. 161-147 4 Claims ABSTRACT OFTHE DISCLOSURE Absorbent pad having a pulp filler, Wadding envelope, andbody contacting cover outside the envelope which is shorter than the padis long, thus to leave end margins of the pad uncovered. The apparatusand method for fabricating such a pad involves superimposing separatepulp mats, one of which is compressed before superimposition in orderthat the compressed mat functions as a flow distribution ply,subdividing the superimposed mats -into discrete pad llers with gapstherebetween, encasing the spaced pad fillers in a wadding envelopewhich is continuous across the gaps, cross sealing the envelope acrossthe gaps to form a continuous wadding envelope tube with linksinterconnecting the spaced ller pads, and applying the body contactingcover sheet thereto.

SUMMARY OF THE INVENTION In accordance with the present invention, animproved pad is produced which has a central compressed or embossed pulplayer which enhances longitudinal and lateral ow distribution and anexternal body contacting cover sheet which is made shorter than the padis long in order to cover only the central part of the pad and leave endmargins of the envelope exposed. The body contacting cover desirablycomprises a smooth strip of non-Woven fabric which is worn against thebody and prevents pilling of the pulp and wadding.

In fabricating the pad, multiple lanes of pulp mat are stripped off of aforming screen onto the laterally adjacent ends of horizontally exibleconveyors. The opposite ends of these conveyors are brought intovertically overlapping relation by horizontally flexing intermediateportions of the conveyors. In the disclosed embodiment, three mats aresuperimposed. The top and bottom mats are left uncompressed. Anintermediate pulp mat is compressed and densied by embossing rolls priorto combining it with the top and bottom layers. This technique reducesthe thickness of the ultimate pad, thus to make it easier to bend andfold the pad to tit body contour. Moreover, the compressed layer hasincreased capillarity, thus to promote lateral distribution of liuidsoutwardly from the pad center and toward its edges, thus to promoteuniform absorption throughout the pad body.

The present invention is distinguished from certain prior art pads inwhich a wadding envelope is made from a single strip folded about oneedge of the pad. In such pads, the edge folding subjects the wadding totension, with undesirable stretching of the wadding. In the presentinvention, the wadding envelope is formed from separate upper and lowerwadding strips which are power fed to eliminate pulling tension whichmight otherwise deform the strips. The upper and lower wadding stripsare laid at against the upper and lower surfaces of the composite pad.The side and end margins of the strips which extend laterally beyond thepad filler are sealed in face relationship. This eliminates all edgefolding and pulling stresses on the wadding.

The pad fillers are longitudinally spaced prior to encasement in thewadding envelope and the gaps between pad llers are sealed with crossseals, thus to form a ice continuous wadding tube with longitudinallyspaced discrete wadding encased pad fillers connected by wadding links.The body contacting cover strip is then fed in face relation against oneside of the continuously moving tube and has cross bands of hot meltadhesive printed thereon in registry with the links. The superimposedtube and body contacting cover strip p ass between a hot melt adhesiveactivating roll set which activates the adhesive and bonds the coverstrip to the links. Thereafter, the links are severed through the bondto produce discrete pads with the characteristics hereinbeforedescribed.

The pad in various appropriate sizes may be used as a hospital underpad,diaper, sanitary napkin, etc.

Other objects, features, and advantages of the invention will appearfrom the following disclosure.

DESCRIPTION OF DRAWINGS FIG. l is a somewhat diagrammatic side viewshowing transfer of the pulp mats from the forming screen onto theflexible conveyors and to a point in the fabrication of the pad slightlybeyond where the wadding strips are introduced, this view being thenrbroken olf and continued in FIG. 2.

FIG. 2 is a continuation of FIG. 1 showing further progress of theensleeved pads. This view shows how the body contacting cover is appliedand the ensleeved pad llers are severed into discrete pads.

FIG. 3 is an enlarged fragmentary plan view of a portion of FIG. 1 andshowing the multiple pad mats stripped from the forming screen andoverlapped by the horizontally exible conveyors.

FIG. 4 is a cross section taken along the line 4-4 of FIG. 3.

FIG. 5 is a somewhat enlarged side view showing the apparatus forconveying the pad tube through the hot melt reactivating rolls and thepad severing knives.

FIG. 6 is an enlarged fragmentary cross section taken along the line 6-6of FIG. 2.

FIG. 7 is an enlarged fragmentary cross section taken along the line 7-7of FIG. 2.

FIG. 8 is an enlarged view, partly in cross section, of the hot meltprinting apparatus for the Ibody contacting cover strip.

FIG. 9 is a perspective view of the printing roll of FIG. 8.

FIG. 10 is a cross section taken along the line 10-10 of FIG. 5.

FIG. 11 s an inverted perspective View of a pad embodying the presentinvention.

FIG. l2 is a cross section taken along the line 12-12 of FIG. ll.

FIG. 13 is a diagrammatic plan view showing the orientation of the padson the conveyor.

yDESCRIPTION `OF PREFERRED EMBODIMENT Although the disclosure hereof isdetailed and exact to enable those skilled in the art to practice theinvention, the physical embodiments herein disclosed merely exemplifythe invention which may be embodied in other specific structure. Thescope of the invention is defined in the claims appended hereto.

In the embodiment illustrated, three pulp mats 20, 21, 22 are formed ona berizer 23 of the .general construction shown in U.S. Pat. 3,268,954and are removed from the iiberizer on a screen 24. As best shown in FIG.3, the respective mats 20, 21, 22 are stripped from the screen 24 ontobelt conveyors 25, 26, 27. These belt conveyors transfer the mats ontothe intake ends of horizontally exible conveyors 31, 32, 33. Theseconveyors are illustrated only diagrammatically in this application. Anysuitable form of iexible conveyor can be used. See, for

example, the flexible conveyors shown in U.S. Pats. 2,872,023, 3,225,898and 3,439,795, the disclosures of which are incorporated herein byreference.

The flexible conveyor belts 31, 32, 33 are flexed horizontally as shownin FIG. 3 so that their discharge ends overlap vertically. Thus, therespective mat strips 20, 21, 22 are deposited one on top of the otheron a takeoff conveyor 34.

It is au important feature of the present invention that theintermediate pulp mat 21 is passed between compression or embossingrolls 35, 36, thus to compress the intermediate mat 21 to less thanabout one-third of its normal thickness, thus densifying theintermediate mat to produce in the ultimate product an intermediatedensied layer which promotes distribution of fluids laterally in thepad. Moreover, the compression of the intermediate pulp mat 21 reducesthe over-all thickness of the pad, thus to facilitate bending andfolding the pad to fit body contours. While in the disclosed embodimentcompressed mat ply 21 is substantially coextensive in area with theuncompressed pulp plies 20, 22, it may be made smaller in one or bothits length and width dimensions.

In corporated immediately on top of the intermediate compressed mat 21is a strip of wadding 37 taken from a parent roll 38. The Wadding strip37 is fed beneath the compression roller 35 and occupies a position inthe pad as shown in FIG. 12.

Top mat 20 is led down by belt conveyor 30, and bottom mat 22 is led upby conveyor 34 to their intersection where all mats join and are fedbeneath cooperating overlying conveyor 40 to a pulp filler cutoff roller41 and its underlying platen roller 42. Rollers 41, 42 cut the mats intodiscrete pulp pad llers 43 which continue on into the apparatus bestshown in FIG. 2.

The discrete pulp llers 43 are conveyed between an upper conveyor belt44 and a lower conveyor belt 45. Belts 44, 45 run at a slightly fasterspeed than the belts 34, 40, thus to produce gaps 46 between successivellers. The pulp llers are further enclosed within a wadding tube orenvelope 39 comprising an upper Wadding strip 47 and a lower waddingstrip 48 which respectively unwind from parent rolls 51, 52.

Strips 47, 48 are slightly wider than the pulp filler 43. Thus, theirside margins are crimped together at 58 by the crimping rolls 53 shownin FIG. 6. Edge waste is cutoli by the combination of a knife roll 54and a platen roll 55, as shown in FIG. 7. In this manner the lillers 43are entubed in a generally flat wadding envelope 39 which consists oftwo strips of wadding laminated in face relation at the edges of thetube.

Beyond the belts 44, 45 the respective fillers 43 are sealed in theenvelope 39 crossways by the cross crimping roller 56 which cooperateswith its platen roller 57, thus to produce cross sealed bands 59 sealingeach pad filler 43 within the tube 39.

The tube 39 then passes through conveyor belts 73, 74, where a bodycontacting cover strip 60 is assembled in face relation to the undersideof the envelope. Strip 60 desirably consists of smooth, soft, non-Wovenfabric unwound from a parent roll 61. The strip 60 has periodicallyprinted upon it a cross band or stripe 62 (FIG. 8) of hot melt adhesive,applied thereto by printing roll 64 in the hot melt adhesive tank 63.Printing roll 64 is immersed in a molten adhesive bath 65. The printingroll 64 has embedded in its periphery intaglio printing bars 69 whichhave dimpled surfaces 66 to retain adhesive picked up in the bath 65. Adoctor blade 67 scrapes from the periphery of the roll 64 all of the hotadhesive, except such as is retained beneath its surface in the dimples66.

The cover strip 60 is narrower than the envelope 39 (FIG. 11) and is fedat a lineal speed equal to the peripheral speed of the printing roll 64and across the roller guides 68 mounted on a carriage 71 on theretractable piston and cylinder assembly 72. The cover strip 60 is fedat the same speed as feed belts 73, 74. The printing bars 69 on roller64 are spaced peripherally a distance exactly equaling the intergapspaces in tube 39. Thus, the printed cross stripes or bands 62 registerwith the tube gaps.

The hot melt adhesive cross bands 62 cool and solidify in the course oftraveling through the apparatus until they reach an adhesive activatingroll set consisting of a heated roll 75 and a platen roll 76. There area series of heating bars 77 on the roll 75. Bars 77 coact with the tube39 in the gaps between successive pads so as to activate the bands 62and cause the body contacting cover strip 60 to adhere to the previouslycrimped cross bands on the tube. As the tube leaves the cross bandactivator 75, the links 78 between successive pads in the tube 39 willbe gripped by the gripping bars 80 on the upper and lower chain feeders81 (FIG. 5). The bars 80 cool and set the activated adhesive bands 62.Feeders 81 transfer the tube 39 to the linal cutoff station whichincludes knife roll A82 and platen roll 83. The rolls 82, 83 areintermediate the ends of conveyor chains 84, 85 which have pad grippingbars 86. Bars 86 are so positioned as to grip the pads, as shown in FIG.5, thus leaving the links 78 between the pads exposed to be cut olf asthey pass between the knife roller `82 and platen roller 83. The nalsevered pad product 90 is then removed on a conveyor 91. FIG. 13illustrates the fact that the pads 90 are formed with their longestdimension transverse to the direction of advance of tube 39 through themachine.

The final pad product is shown in FIGS. 11 and l2 (inverted as comparedto previous views). As is clear from FIG. 11, the body contacting coverstrip 60 is not as long as the pad, thus to leave the end margins of thepad uncovered. Moreover, the strip 60 is applied to only one face of thepad. This construction is particularly advantageous Where the pad 90 isused as a diaper and the diaper is folded about the baby. Accordingly,the body contacting cover 60 is located only over the central portion ofthe diaper which becomes soiled and wet, thus to prevent pilling of thepulp and wadding in that affected area. A substantial saving is thusmade in the amount of cover material needed for each pad.

An important feature of the present invention is the method andapparatus by which undue stresses on the wadding strips 37, 47, 48 areavoided. In the Iirst place, the wadding strips are not folded aroundthe edges of the pads as in some prior art pads. Such folding producestension in the wadding, thus tending to stretch the Wadding and possiblypull it out of shape or tear it. In the present apparatus and method,the wadding strips are simply laid in parallel superimposed relation.The edge margins of strips 47, 48 are overlapped and crimped, as shownin FIG. 6. This avoids any necessity for stretching or imposing pressureon the wadding as would other- Wise be required if it were folded orpulled around the edges of the pad.

Moreover, each Wadding strip is relieved of the necessity for pulling itfrom the parent rolls 38, 51, 52. This is accomplished by providing eachparent roll with a powered belt driver 92. The belt drivers 92 drive theparent rolls so as to unwind the strips under power, and relieve thestrips of tension which would otherwise be induced in the strips.Accordingly, for this additional reason, the wadding strips are notstretched or otherwise distorted in the course of formation of the tubein which the pad llers are encased.

The completed pad, as shown in FIGS. ll and l2, contains a mid layer 21of compressed pulp and outside layers 20, 22 of uncompressed pulp. Thecompressed layer 21 promotes rapid lateral ilow of fluids, thus topromote uniform absorption of fluid in all of the pulp material in thepad.

I claim:

1. In an absorptive pad having a pulp ller, an absorbent weddingenvelope and an absorbent body contacting cover outside the envelope,the improvement in which said body contacting cover is at one side ofthe pad only, is shorter than the pad is long, and is disposed at thecenter of said one side of the pad to leave absorbent end margins of thepad uncovered, said wadding envelope comprising two wadding plies havingperipheral margins in face relation, said body contacting cover havingside margins attached in face relation to portions of the peripheralmargins of the wadding plies.

2. The pad of claim 1 in which the side margins of the body contactingcover are attached to portions of the peripheral margins of one of thewadding plies by stripes of hot melt adhesive.

3. The pad of claim 1 in which the pulp ller includes at least one layerof substantially uncompressed pulp 15 mat and another layer ofcompressed pulp mat.

4. The pad of claim 1 in which the peripheral margins of the waddingenvelope are held together by crimps.

References Cited UNITED STATES PATENTS 2,890,700 6/ 1959 Lonberg-Holm128-284 3,424,163 1/ 1969 Gravdahl 128-290 2,787,271 4/ 1957 Clark12'8--290 2,682,873 7/ 1954 Evans et al 128-296 X 3,294,090 12/ 1966Younger 128-290 3,315,676 4/1967 Cooper 161-151 X 10 3,344,789 10/ 1967Arnold et al 128-287 FOREIGN PATENTS 269,399 4/ 1927 Great Britain128-296 WILLIAM A. POWELL, Primary Examiner U.S. Cl. X.R.

